News & Events






Hottopic
18/12/2019 10h00
Noémie DEPRET from Montcouquiol-Sans's lab will give a presentation entitled "To be announced"
2019-12-18 10:00:00 2019-12-18 10:45:00 Europe/Paris Noémie DEPRET 0

Hottopic
18/12/2019 10h45
Sourav GHOSH from Frick's lab will give a presentation entitled "To be announced"
2019-12-18 10:45:00 2019-12-18 11:30:00 Europe/Paris Sourav GHOSH 0

PhD/HDR defense
09/12/2019 14h00
Zhe ZHAO from Marsicano's lab will give a presentation entitled 'Role of the type-1 cannabinoid receptor in the control of water intake.' Role of the type-1 cannabinoid receptor in the control of water intake
2019-12-09 14:00:00 2019-12-09 16:00:00 Europe/Paris Zhe ZHAO from Marsicano's lab will give a presentation entitled 'Role of the type-1 cannabinoid receptor in the control of water intake.' 0

Role of the type-1 cannabinoid receptor in the control of water intake
Thesis supervisor: Giovanni MARSICANO PhD

Water intake is crucial for maintaining body fluid homeostasis and animals’ survival. Complex brain processes trigger thirst, which arises upon losing blood volume (i.e. extracellular dehydration) or increasing blood osmolality (i.e. intracellular dehydration), to replenish water for fluid balance. The brain plays a key role in modulating these processes, but the central mechanisms regulating water intake are not fully understood. Type-1 cannabinoid receptors (CB1) are widely and abundantly expressed in the central nervous system where they modulate a variety of functions, such as memory, anxiety and feeding behavior. However, the role of CB1 receptors in the control of water intake is still a matter of debate, since pharmacological activation or blockade of CB1 receptors produced contradictory results in drinking behavior experiments.
My thesis work focuses on the role of CB1 receptors in the control of water intake. By using genetic, pharmacological, anatomical, imaging, and behavioral approaches, I examined the involvement of CB1 receptors in the control of water intake induced by different physiological conditions of extracellular or intracellular dehydration. The results showed that CB1 receptor signaling is required to promote water intake. In particular, global deletion of CB1 receptors does not change plasma osmolality and body water composition, but it decreases water intake induced by water deprivation, systemic or intracerebroventricular (ICV) administration of sodium chloride, or ICV injection of the peptide hormone angiotensin II. In the attempt to better detail the neuronal mechanisms of this function, I discovered that the presence of CB1 receptors in cortical glutamatergic neurons, particularly the ones located in the anterior cingulate cortex (ACC) glutamatergic neurons promote drinking behavior. CB1 receptors are abundantly expressed in axon terminal of ACC glutamatergic neurons projecting to the basolateral amygdala (BLA) and selective expression of CB1 receptors in this circuit is sufficient to guarantee proper drinking behavior in mice. Altogether, these data reveal that CB1 receptors are necessary to promote water intake, and that their presence in the ACC-BLA circuit is sufficient for the top-down control of drinking behavior.
Furthermore, I also provided evidence that CB1 controls water intake in different conditions at other levels, e.g. insular cortex, cholinergic cells, and mitochondria.
In summary, my thesis work analyzed the role of CB1 receptors in distinct cell populations/neuronal circuits for the control of water intake. These results will help further understanding the functions of the ECS and the brain regulation of thirst.

Date de la soutenance: 09/12/2019 - 14h00
Lieu: Centre Broca Nouvelle-Aquitaine Conference Room



On 3 December 2019, Andreas Frick received the Marcel Dassault Award for his work on the processing of sensory information in the ASD.




Hottopic
27/11/2019 10h00
Valentine LE GALL from Herry's lab will give a presentation entitled "What is the role of the prefrontal cortex in the selection of innate fear responses ?".

Hottopic
27/11/2019 10h30
Ismail KOUBIYR from Oliet's lab will give a presentation entitled ' The reorganization of human brain networks in the early stage of multiple sclerosis.'


A post-doc position in electrophysiology, optogenetics and functional imaging is available in the group of Dr. Nathalie Sans (Neurocentre Magendie).

We are looking for highly motivated researchers to analyse and manipulate hippocampal circuits involved in specific behavioural paradigms. The successful candidate is expected to have a strong interest in neuroscience with an expertise in whole-cell patch clamp, optogenetics and/or viral manipulation (preferably in the DG-CA3 network). The offered position is part of ongoing projects regarding the plasticity of the hippocampal network organization under pathophysiological conditions.

The ideal candidate should have a Ph.D. degree in neuroscience, physiology, or a related field (within the past five years and ideally is less than 35 years old). Candidates should be highly self-motivated, energetic, able to work independently and in collaboration.
There is some flexibility in the starting date, with preference within the first semester of 2020.

Applications should include a detailed CV with publication list, a brief statement of research experience and interests and at least two references to Dr. Nathalie Sans.

Contract length: 2 years

Contact

Nathalie Sans
nathalie.sans@inserm.fr




General informations
21/11/2019
Cyril Herry, an influential researcher!

Thanks to the 5200 citations of his work, Cyril Herry appears in the ranking Clarivate Analytics of the most influential researchers in the last 10 years. This ranking is based on data and analysis through ralises bibliomtriques experts from the Institute for Scientific Information Web of Science Group. The Web of Science Group recognizes 6 216 scientists who have demonstrated significant influence your product using their peers by publishing numerous articles that rank among the 1% most cits per domain per year. The analysis covers the period 2008-2018. Only 10 other researchers from Inserm and 4 others from the University of Bordeaux are included in this ranking. Congratulations Cyril!




PhD/HDR defense
21/11/2019 14h00
Olivier DUBANET Dynamics of interactions between excitation and perisomatic inhibition in the normal and epileptic hippocampal circuit in vivo.

Dynamics of interactions between excitation and perisomatic inhibition in the normal and epileptic hippocampal circuit in vivo.
Directeur de thèse : Xavier Leinekugel
Date de la soutenance: 21/11/2019 - 14h00
Lieu: Magendie Salle de conference


PhD/HDR defense
14/11/2019 14h00
de Thèse – Ashley Castellanos Jankiewicz Bile acids signaling as a novel mechanism in the hypothalamic control of energy balance

Bile acids signaling as a novel mechanism in the hypothalamic control of energy balance

Thesis supervisor:
Daniela Cota, MD, HDR

Summary: Bile acids (BA) are cholesterol-derived molecules mostly known for participating in the digestion of lipids. By activating the Takeda G protein coupled receptor 5 (TGR5) in peripheral organs, BA can also act as signaling molecules to reduce body weight, increase energy expenditure and improve glycaemia. These outcomes imply an anti-obesity function for TGR5. Since the major center of convergence of nutrient, hormonal, and environmental cues is the brain, particularly the hypothalamus, we hypothesized a role for TGR5 in this brain structure, specifically under diet-induced obesity.

Our results show that TGR5 and BAs transporters are expressed in the mediobasal hypothalamus (MBH), and that obese mice have decreased circulating and hypothalamic BA levels. Acute intracerebroventricular (ICV) or intra-MBH administration of TGR5 agonists reduced food intake and body weight in obese mice only, and improved insulin sensitivity. Accordingly, chronic ICV administration of the TGR5 agonist in obese mice reduced their body weight and adiposity, while increasing energy expenditure and markers of sympathetic activity in the adipose tissue. Indeed, experiments conducted at thermoneutrality (30°C) or chemical sympathectomy blunted these effects, demonstrating that central TGR5 effects require the engagement of the sympathetic nervous system. Conversely, by using genetic animal models, we observed that the deletion of TGR5 in the MBH rapidly increased food intake, body weight and adiposity, while blunting the sympathetic response to a cold challenge (4h at 4°C), hence worsening obesity.

Our work proves the existence of a functional hypothalamic BA – TGR5 receptor system. We show for the first time that the activation of TGR5 in the MBH decreases body weight and adiposity, while increasing energy expenditure through recruitment of the sympathetic nervous system. These results expose a new mechanism of action for potential anti-obesity therapies.

Keywords: Bile acids, TGR5, diet-induced obesity, mediobasal hypothalamus, energy balance, sympathetic activity, thermogenesis.
Date de la soutenance: 14/11/2019 - 14h00
Lieu: Neurocentre Magendie Seminar room